/Engine/Plugins/Online/OnlineServices/Source/OnlineServicesCommon/Public/Online/SessionsCommon.h
This event will trigger as a result of accepting a session invite or joining a session via the platform UI.
virtual [TOnlineEvent](API\Plugins\OnlineServicesInterface\Online\TOnlineEvent)< void(const [FUISessionJoinRequested](API\Plugins\OnlineServicesInterface\Online\FUISessionJoinRequested) &)> OnUISessionJoinRequested()